题目描述
Problem Statement
You are given a connected simple undirected graph consisting of N vertices and M edges.
For $i = 1, 2, \ldots, M$, the i-th edge connects vertex u_i and vertex v_i.
Takahashi starts at Level 0 on vertex 1, and will perform the following action exactly K times.
- First, choose one of the vertices adjacent to the vertex he is currently on, uniformly at random, and move to the chosen vertex.
- Then, the following happens according to the vertex v he has moved to.
- If C_v = 0: Takahashi's Level increases by 1.
- If C_v = 1: Takahashi receives a money of X^2 yen, where X is his current Level.
Print the expected value of the total amount of money Takahashi receives during the K actions above, modulo 998244353 (see Notes).
Input
The input is given from Standard Input in the following format:
N M K
u_1 v_1
u_2 v_2
$\vdots$
u_M v_M
$C_1 C_2 \ldots C_N$
Output
Print the answer.
Constraints
- $2 \leq N \leq 3000$
- $N-1 \leq M \leq \min\lbrace N(N-1)/2, 3000\rbrace$
- $1 \leq K \leq 3000$
- $1 \leq u_i, v_i \leq N$
- $u_i \neq v_i$
- $i \neq j \implies \lbrace u_i, v_i\rbrace \neq \lbrace u_j, v_j \rbrace$
- The given graph is connected.
- $C_i \in$ $\lbrace 0, 1\rbrace$
- All values in the input are integers.
Sample Input 1
5 4 8
4 5
2 3
2 4
1 2
0 0 1 1 0
Sample Output 1
89349064
Among the multiple paths that Takahashi may traverse, let us take a case where Takahashi starts on vertex 1 and goes along the path $1 \rightarrow 2 \rightarrow 4 \rightarrow 5 \rightarrow 4 \rightarrow 2 \rightarrow 1 \rightarrow 2 \rightarrow 3$, and compute the total amount of money he receives.
- In the first action, he moves from vertex 1 to an adjacent vertex, vertex 2. Then, since C_2 = 0, his Level increases to 1.
- In the second action, he moves from vertex 2 to an adjacent vertex, vertex 4. Then, since C_4 = 1, he receives 1^2 = 1 yen.
- In the third action, he moves from vertex 4 to an adjacent vertex, vertex 5. Then, since C_5 = 0, his Level increases to 2.
- In the fourth action, he moves from vertex 5 to an adjacent vertex, vertex 4. Then, since C_4 = 1, he receives 2^2 = 4 yen.
- In the fifth action, he moves from vertex 4 to an adjacent vertex, vertex 2. Then, since C_2 = 0, his Level increases to 3.
- In the sixth action, he moves from vertex 2 to an adjacent vertex, vertex 1. Then, since C_1 = 0, his Level increases to 4.
- In the seventh action, he moves from vertex 1 to an adjacent vertex, vertex 2. Then, since C_2 = 0, his Level increases to 5.
- In the eighth action, he moves from vertex 2 to an adjacent vertex, vertex 3. Then, since C_3 = 1, he receives 5^2 = 25 yen.
Thus, he receives a total of 1 + 4 + 25 = 30 yen.
Sample Input 2
8 12 20
7 6
2 6
6 4
2 1
8 5
7 2
7 5
3 7
3 5
1 8
6 3
1 4
0 0 1 1 0 0 0 0
Sample Output 2
139119094
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分